Square bottomed plastic bag and method of making same

ABSTRACT

A square bottom plastic bag is designed to stand upright when opened. The bags are constructed with open tops, side gussets, side handle openings or with t-shirt style handles. The t-shirt bags may have apertures through the handles to suspend the bags on a rack. The bags may have detachable or rupturable center tabs. The bags may have openings, microperforations, or are formed of porous material to dissipate heat or moisture. The bags are formed from a flattened gusseted tube of polyethylene cut into bag blanks of a selected length. The blank is slit upwardly from its lower end and portions of the front and back panels and side gussets are folded and sealed to form a square, flat bag bottom.

RELATED APPLICATIONS

The instant application is a Continuation of Divisional application Ser.No. 11/058,637, filed Feb. 15, 2005, of U.S. patent application Ser. No.10/779,501, filed Feb. 13, 2004. No new matter has been added.

FIELD OF INVENTION

The invention pertains to plastic bags and methods of manufacturingthem. More particularly, the invention relates to square bottomed bagswith t-shirt bag style handles.

BACKGROUND OF THE INVENTION

Plastic bags have replaced paper bags for many applications in recentyears based upon the ease and economics with which they can bemanufactured. However, at present, paper bags are still favored forcertain applications. Paper bags can easily be constructed with acompletely flat bottom and can be made to stand up without a supportingrack both when empty and when filled. Also, paper bags tend to besomewhat porous and “breathable” and thus more desirable for use withitems such as hot food products. For these reasons, paper bags havedominated such industries as fast food delivery and other applicationsin which it is important to be able to easily position articles withinthe bag. Paper bags, on the other hand, have other problems. Forexample, strong handles are not easily attached to paper bags, the bagsbecome weakened with moisture, they are heavy, bulky and require wood asraw material. Plastic bags, on the other hand, are more durable, morecompact and light weight, stronger, impervious to moisture and caneasily be made with strong handles.

Various designs have been developed in attempts to provide a practical,breathable, square bottomed plastic bag that will stand up when openedfor filling and remain upright when filled. U.S. Pat. No. 6,286,681issued to Wilfong, Jr. et al. is directed to a ventilated plastic bagembodying closely spaced micro-perforations that extend through the wallsections to provide ventilation to the interior food carrying area.These perforations allow the bag to be used for carrying hot food itemswithout weakening the strength regions of the bag. The closed bottomarea of the bag may be formed by heat-sealing of the film material, butmay also include corner or angle seals to define a square bottom on thebag.

U.S. Application Publication No. 2002/0110290 by Gebhardt discloses aplastic bag with randomly placed arcurate vent pairs. The bags describedin this publication are made from a plastic tubing or sheeting stock.The bag may also include a handle aperture and the bag may includesquare-bottomed seals on gusseted bags. In the preferred embodiment ofthe receptacle described, vents are cut into the material of thereceptacle that can accommodate, store, and transport fresh hot foods toprovide a breathable element desired for the bags.

U.S. Pat. No. 6,319,184 issued to DeMatteis is directed to an apparatusand process for producing cold seal in plastic bags. The bags describedmay be of a semi-flat-bottom type and may have hand holes to formhandles in the upper portion of the bags. U.S. Pat. No. 6,113,269 issuedto DeMatteis discloses an automatic ventilating system for plastic bags.U.S. Pat. No. 6,095,687 issued to DeMatteis is directed to a flatbottomed plastic bag having a handle aperture. The bag described sitsupright upon a bottom gusset.

U.S. Pat. No. 5,149,201 issued to Benoit discloses a bag structure of athermoplastic film material comprising front and rear bag wallsconnected by side walls and having an open mouth top portion, said openmouth portion being characterized by having handles located at oppositeend regions thereof, said handles being of two films as a result ofbeing integral extensions of said front rear and gusseted side walls,said bag having a bottom wall planarly extensible so as to form arectangle with at least no substantial excess film outside of the bulkvolumetric capacity of said bottom region of said bag. This inventionalso provides a method and system for preparing flat bottomthermoplastic sacks comprising process steps and means for forming atube of thermoplastic film, collapsing said tube while forming twooppositely disposed gussets therein, forming two pairs of diagonalsealed seams in the gussets, forming a transverse sealed seam across thetube along a line which includes the inboard ends of the diagonal seamsand forming pre-weakened transverse lines closely adjacent to saidtransverse sealed seam or forming a severing line along this line,removing the four double triangular regions bounded by the diagonalseams, the transverse seams and the side edges of the tube andcollecting the resulting structures either while still interconnected orby stacking the severed sacks. The final structure can have handles orit can be handleless.

U.S. Pat. No. 5,165,799 issued to Wood describes flexible square bottombags which include side gusset panels having central inwardly orientedfin seams and which are sealed adjacent their lowermost corners toportions of the front and rear panels of the bags and wherein the entirewidth of the lowermost edges of the front and rear panels are sealed tothereby form bags having bottoms reinforced by triangular gusset sealsat each corner and which have an outwardly oriented transverse bottomfin seam when erected.

U.S. Pat. No. 5,362,152 issued to Fletcher et al. describes a T-shirttype plastic bag adapted for carrying hot foods from fast foodrestaurants. The bag includes front and rear wall sections, gussettedside wall sections integrally connecting the front and rear wallsections together and means connecting the bottoms of the front, rearand gussetted side wall sections together to define a closed bottom. Atleast a part of the front and rear wall sections are open at the tops todefine a mouth portion. Laterally spaced handles are integral with thefront, rear and gussetted side wall sections and extend upwardly fromopposed sides of the mouth portion. Apertures extend through at leastone of the wall sections for providing a path for a venting air flowfrom the outside of the bag and through the inside of the bag when thebag is carrying hot food.

U.S. Pat. No. 5,102,384 issued to Ross et al. discloses a method ofconstructing a flat bottom in a plastic film tube having an open upperend, a closed lower end formed by a transverse seal, forward andrearward sides and a pair of opposing pleated sides that interconnectthe forward and rearward sides. The method includes the steps ofreleasably engaging a lower vacuum and a lower clamp with a transversesection of the rearward side of the tube to provisionally hold thetransverse section. A lateral section of the forward side is gripped andraised by an upper vacuum and an upper clamp to expose a portion of thepleated sides such that first and second pockets are formed,respectively, in the sides. The sealed lower end is drawn toward theupper end to fold the tube along first and second transverse fold linesin the forward side, along a third transverse fold line in thetransverse section of the rearward side, and along fourth and fifth foldlines, respectively, in the pleated sides such that the first and secondpockets are located in the pleated sides, respectively between the firstand third fold lines and the lower end of the bag. Pressure is appliedto the tube to form creases along the first, third, fourth and fifthfold lines, which define the perimeter of the flat bottom of the tube.

U.S. Pat. No. 5,549,538 issued to Marsik describes a process formanufacturing a multi-ply square bottom bag having a front wall, a backwall, a pair of gusseted side walls, each of which join to said frontand back walls. There is also formed a gusseted square bottom panelhaving spaced but substantially parallel gusset edges and said bottom isjoined to the front, back and side walls. The bag is produced byproviding a web of inner ply material and a web of outer ply material,adhesively joining said webs into a composite and forming said bag fromsaid joined webs. The improvement relates to forming a first flap in theinner web by cutting the web so as to form a plurality of free edges anda hinge line for said flap. The hinge line is connected to the freeedges so that the free edges and hinge line define the flap. Thereafterjoining the inner and outer webs to form the composite web. The hingeline is generally transverse to the longitudinal axis of the web and theflap is formed in the inner web so as to be positioned adjacent thefront wall and bottom wall with the hinge line at the junction thereofwhen said bag is formed and said flap is arranged to overlie the gussetedges in the bottom panel.

It is an objective of the present invention to provide a square bottomedbag with integral t-shirt style handles formed in an upper portion ofthe bag. It is a further objective to provide square bottomed bags thatwill remain upright when opened in filled or unfilled condition. It is astill further objective of the invention to provide a breathable orventilated bag suitable for use with hot food or similar items. It isyet a further objective to provide bags that have the above-describedfeatures that are easily and inexpensively manufactured.

While some of the objectives of the present invention are disclosed inthe prior art, none of the inventions found include all of therequirements identified.

SUMMARY OF THE INVENTION

The present invention addresses all of the deficiencies of prior artsquare bottom bag stack inventions and satisfies all of the objectivesdescribed above.

(1) A square bottomed plastic bag providing the desired features may beconstructed from the following components. Front and rear polyethylenefilm walls are provided. Each of the front and rear walls have first andsecond side edges, a top edge and a bottom edge. The bag has a pair oflongitudinally oriented side gussets attached to the first and secondside edges. The bag has a flat, rectangular bottom formed of lowerportions of the front and rear walls and lower portions of the sidegussets. Lower corners of the each side gusset are folded outwardly andtogether to form downward pointing triangular panels. The triangularpanels are folded inwardly from the side gussets. Lower portions of thefront and rear walls are folded inwardly and sealed together to form thebag bottom. The bag bottom is sealed to the side gussets adjacent upperedges of the triangular panels. The triangular panels are sealed to anupper surface of the bag bottom. When the bag is opened, it will standerect upon the flat bottom.

(2) In a variant of the invention, the bag is folded inwardly at theside gussets and upwardly from either of the front wall and the rearwall at a point spaced upwardly from the bottom edge, to form aflattened bag.

(3) In a further variant, the square bottomed plastic bag furtherincludes at least one handle opening. The handle opening extends throughthe front and rear walls in an upper portion of each of the bags.

(4) In still a further variant, the bags are formed of a porousmaterial.

(5) In yet a further variant, the bags are formed of material hasmicroperforations penetrating at least a portion of any of the bag wallsand side gussets.

(6) In another variant of the invention, the bags have a plurality ofventilating openings penetrating at least a portion of any of the bagwalls and side gussets.

(7) In still another variant, the bag includes an upper seal. The upperseal joins the front wall to the rear wall at the top edges of the bagwalls and joins top edges of the side gussets. A U-shaped cutout isprovided. The cutout commences at a first point on the upper seal spacedfrom the first side edge and extends downwardly toward the bottom edges,across an upper portion of the bag walls and upwardly to a second pointon the upper seal spaced from the second side edge, thereby forming anopen bag mouth and a pair of bag handles terminating at the upper seal.

(8) In yet another variant, the bag includes a pair of apertures. Eachof the apertures penetrates the bag handles at a point spaced downwardlyfrom the upper seal. The apertures permit the bag to be suspended from adispensing rack.

(9) In still another variant, a central tab extends upwardly from atleast one of the front wall and the rear wall at the open mouth. Thecentral tab has an opening through it for suspending the bag from adispensing rack.

(10) In a further variant, the central tab is attached to at least oneof the front wall and the rear wall at the open mouth at a weakenedarea. The weakened area permits the central tab to be torn from the openmouth of the bag as the bag is removed from a dispensing rack.

(11) In still a further variant, the central tab includes a weakenedarea. The weakened area extends from the opening to an edge of thecentral tab. The weakened area parts under pressure as the bag isremoved from a dispensing rack.

(12) A method of making a square bottomed plastic bag, includes thesteps of: extruding a tube of thermoplastic material. Forming sidegussets in the tube and flattening same. Cutting the flattened tubeperpendicular to the side gussets to a first predetermined length,thereby forming a bag blank. The bag blank has front and rear walls,front and rear top edges, front and rear bottom edges, first and secondside edges. Slitting the bag blank at intersections of the side gussetsand the front and rear walls from the front and rear bottom edgesupwardly for a first predetermined distance. Folding lower corners ofthe each side gusset outwardly and together to form downward pointingtriangular panels. Folding the triangular panels inwardly from the sidegussets. Folding lower portions of the front and rear walls inwardly.Sealing the front and rear wall together adjacent the front and rearbottom edges to form a bag bottom. Sealing the bag bottom to the sidegussets adjacent upper edges of the triangular panels. Sealing thetriangular panels to an upper surface of the bag bottom.

(13) A variant of the method, includes the additional step of foldingthe bag inwardly at the side gussets and upwardly from either of thefront wall and the rear wall at a point spaced upwardly from the bottomedge, to form a flattened bag.

(14) Another variant of the method includes the steps of: Extruding atube of thermoplastic material. Forming side gussets in the tube andflattening same. Cutting the flattened tube perpendicular to the sidegussets to a first predetermined length, thereby forming a bag blank.The bag blank has front and rear walls, front and rear top edges, frontand rear bottom edges, first and second side edges. Forming a creaseline in the bag blank. The crease line is parallel to the bottom edgesand spaced upwardly from the bottom edges by approximately one half of awidth of one of the side gussets. Slitting the bag blank from the bottomedges of the walls to the crease line at each intersection of the frontand rear walls and the side gussets. Folding lower corners of the eachside gusset outwardly to the crease line and together to form downwardpointing triangular panels. Folding the triangular panels inwardly fromthe side gussets at the crease line. Folding lower portions of the frontand rear walls inwardly from the crease line. Sealing the front and rearwall together adjacent the front and rear bottom edges to form a bagbottom. Sealing the bag bottom to the side gussets adjacent the creaseline and upper edges of the triangular panels. Sealing the triangularpanels to an upper surface of the bag bottom.

(15) Still another variant of the method includes the additional step offolding the bag blank inwardly at the side gussets and upwardly fromeither of the front wall and the rear wall at the crease line, to form aflattened bag.

(16) Yet another variant of the method includes the step of cutting atleast one handle opening in the bag, the handle opening extendingthrough the front and rear walls in an upper portion of the bag.

(17) A further variant of the method includes the step of forming thebag of a porous material.

(18) Yet a further variant of the method includes the step of formingmicroperforations penetrating at least a portion of any of the bag wallsand side gussets.

(19) Still a further variant of the method includes the step of forminga plurality of ventilating openings penetrating at least a portion ofany of the bag walls and side gussets.

(20) Another variant of the method includes the steps of: Joining thefront wall to the rear wall at the top edges of the bag walls andjoining top edges of the side gussets, thereby forming an upper seal.Forming a U-shaped cutout, the cutout commencing at a first point on theupper seal spaced from the first side edge and extending downwardlytoward the bottom edges, across an upper portion of the bag walls andupwardly to a second point on the upper seal spaced from the second sideedge, thereby forming an open bag mouth and a pair of bag handlesterminating at the upper seal.

(21) Still another variant of the method includes the step of cutting apair of apertures. Each of the apertures penetrates the bag handles at apoint spaced downwardly from the upper seal. The apertures permit thebag to be suspended from a dispensing rack.

(22) Yet another variant of the method includes the step of forming acentral tab. The central tab extends upwardly from at least one of thefront wall and the rear wall at the open mouth. The central tab has anopening through it for suspending the bag.

(23) A further variant of the method includes the step of forming aweakened area. The weakened area attaches the central tab to at leastone of the front wall and the rear wall at the open mouth. The weakenedarea permits the central tab to be torn from the open mouth of the bagas the bag is removed from a dispensing rack.

(24) In a final variant of the method includes the step of forming thecentral tab with a weakened area. The weakened area extends from theopening to an edge of the central tab. The weakened area parting underpressure as the bag is removed from a dispensing rack.

An appreciation of the other aims and objectives of the presentinvention and an understanding of it may be achieved by referring to theaccompanying drawings and the detailed description of a preferredembodiment.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a gusseted open mouth bag blank formedfrom a section of gusseted tubing illustrating slitting of lower cornersof the tube;

FIG. 2 is a perspective view of the FIG. 1 embodiment illustrating theoutward folding of lower ends of the side gussets to form triangularportions;

FIG. 3 is a perspective view of the FIG. 1 embodiment illustrating theinward folding of the triangular portions of the bag blank;

FIG. 4 is a perspective view of the FIG. 1 embodiment illustrating a bagbottom formed from lower portions of the front and rear bag wallssecured to each other and the ends of the side gussets;

FIG. 5 is a perspective view of the FIG. 1 embodiment illustrating thefolding of the bag bottom along side the bag walls;

FIG. 6 is a perspective view of the FIG. 1 embodiment illustrating a bagwith central handles;

FIG. 7 is a perspective view of the FIG. 1 embodiment illustrating a bagwith ventilating openings penetrating at least a portion of the bagwalls and side gussets;

FIG. 8 is a front elevational view of a t-shirt style square bottom bagwith center tab;

FIG. 9 is a front elevational view of a second embodiment of a t-shirtstyle square bottom bag having hanging apertures in the handles;

FIG. 10 is a front elevational view of a fourth embodiment of a t-shirtstyle square bottom bag having a removable center tab joined to the bagwith a frangible area;

FIG. 11 is a front elevational view of a third embodiment of a t-shirtstyle square bottom bag having a center tab with a weakened area betweenthe tab opening and the edge of the bag mouth;

FIG. 12 is a perspective view of an apparatus for forming the bags ofthe FIG. 1 embodiment including gusseting and slitting the extrudedtubing;

FIG. 13 is a perspective view of the method of folding the lower ends ofthe bag gussets outwardly to form triangular portions;

FIG. 14 is a perspective view of the method of folding the triangularportions inwardly as part of the bag bottom;

FIG. 15 a perspective view of the method of folding the front and rearbag walls over the triangular portions and fastening them to each other,the triangular portions and the side gussets to form the bag bottom;

FIG. 16 is a bottom side view of the assembled bag illustrating thebottom and side seams; and

FIG. 17 is a perspective view of a method of forming a gusseted t-shirtstyle bag as in the FIG. 21 embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(1) As illustrated in FIGS. 1-4, a square bottomed plastic bag 10providing the desired features may be constructed from the followingcomponents. Front 14 and rear 18 polyethylene film walls are provided.Each of the front 14 and rear 18 walls have first 22 and second 26 sideedges, a top edge 30 and a bottom edge 34. The bag 10 has a pair oflongitudinally oriented side gussets 38 attached to the first 22 andsecond 26 side edges. The bag 10 has a flat, rectangular bottom 42formed of lower portions 46 of the front 14 and rear 18 walls and lowerportions 50 of the side gussets 38. As illustrated in FIG. 2, lowercorners 54 of the each side gusset 38 are folded outwardly and togetherto form downward pointing triangular panels 58. As illustrated in FIG.3, the triangular panels 58 are folded inwardly from the side gussets38. As illustrated in FIG. 4, lower portions 46 of the front 14 and rear18 walls are folded inwardly and sealed together to form the bag bottom42. The bag bottom 42 is sealed to the side gussets 38 adjacent upperedges 62 of the triangular panels 58. The triangular panels 58 aresealed to an upper surface 66 of the bag bottom 42. When the bag 10 isopened, it will stand erect upon the flat bottom 42.

(2) In a variant of the invention, as illustrated in FIG. 5, the bag 10is folded inwardly at the side gussets 38 and upwardly from either ofthe front wall 14 and the rear wall 18 at a point 70 spaced upwardlyfrom the bottom edge 34, to form a flattened bag 10.

(3) In a further variant, as illustrated in FIG. 6, the square bottomedplastic bag 10 further includes at least one handle opening 74. Thehandle opening 74 extends through the front 14 and rear 18 walls in anupper portion 78 of each of the bags 10.

(4) In still a further variant, the bags 10 are formed of a porousmaterial 82.

(5) In yet a further variant, the bags 10 are formed of material hasmicroperforations 84 penetrating at least a portion of any of the bagwalls 14, 18 and side gussets 38.

(6) In another variant of the invention, as illustrated in FIG. 7, thebags 10 have a plurality of ventilating openings 86 penetrating at leasta portion of any of the bag walls 14, 18 and side gussets 38.

(7) In still another variant, as illustrated in FIG. 8, the bag 10includes an upper seal 90. The upper seal 90 joins the front wall 14 tothe rear wall 18 at the top edges 30 of the bag walls 14, 18 and joinstop edges 94 of the side gussets 38. A U-shaped cutout 98 is provided.The cutout 98 commences at a first point 102 on the upper seal 90 spacedfrom the first side edge 22 and extends downwardly toward the bottomedges 34, across an upper portion 78 of the bag walls 14, 18 andupwardly to a second point 106 on the upper seal 90 spaced from thesecond side edge 26, thereby forming an open bag mouth 110 and a pair ofbag handles 114 terminating at the upper seal 90.

(8) In yet another variant, as illustrated in FIG. 9, the bag 10includes a pair of apertures 118. Each of the apertures 118 penetratesthe bag handles 114 at a point 122 spaced downwardly from the upper seal90. The apertures 118 permit the bag 10 to be suspended from adispensing rack 126.

(9) In still another variant, as illustrated in FIG. 10, a central tab130 extends upwardly from at least one of the front wall 14 and the rearwall 18 at the open mouth 110. The central tab 130 has an opening 134through it for suspending the bag 10 from a dispensing rack (not shown).

(10) In a further variant, the central tab 130 is attached to at leastone of the front wall 14 and the rear wall 18 at the open mouth 110 at aweakened area 138. The weakened area 138 permits the central tab 130 tobe torn from the open mouth 110 of the bag 10 as the bag 10 is removedfrom a dispensing rack.

(11) In still a further variant, as illustrated in FIG. 11, the centraltab 130 includes a weakened area 142. The weakened area 142 extends fromthe opening 134 to an edge 146 of the central tab 130. The weakened area142 parts under pressure as the bag 10 is removed from a dispensing rack126.

(12) A method of making a square bottomed plastic bag 10, as illustratedin FIGS. 12-16, includes the steps of: extruding a tube of thermoplasticmaterial 150. Forming side gussets 38 in the tube 150 and flatteningsame. Cutting the flattened tube 150 perpendicular to the side gussets38 to a first predetermined length 154, thereby forming a bag blank 158.As illustrated in FIG. 13, the bag blank 158 has front 14 and rear 18walls, front and rear top edges 30, front and rear bottom edges 34,first 22 and second 26 side edges. Slitting the bag blank 158 atintersections of the side gussets 38 and the front 14 and rear 18 wallsfrom the front and rear bottom edges 34 upwardly for a firstpredetermined distance 162. As illustrated in FIG. 14, folding lowercorners 54 of the each side gusset 38 outwardly and together to formdownward pointing triangular panels 58. Folding the triangular panels 58inwardly from the side gussets 38. As illustrated in FIG. 15, foldinglower portions 46 of the front 14 and rear 18 walls inwardly. Sealingthe front 14 and rear 18 wall together adjacent the front and rearbottom edges 34 to form a bag bottom 42. Sealing the bag bottom 42 tothe side gussets 38 adjacent upper edges 62 of the triangular panels 58.Sealing the triangular panels 58 to an upper surface 66 of the bagbottom 42.

(13) A variant of the method, as illustrated in FIG. 5, includes theadditional step of folding the bag 10 inwardly at the side gussets 38and upwardly from either of the front wall 14 and the rear wall 18 at apoint 70 spaced upwardly from the bottom edge 34, to form a flattenedbag 10.

(14) Another variant of the method, as illustrated in FIGS. 12-16,includes the steps of: Extruding a tube of thermoplastic material 150.Forming side gussets 38 in the tube 150 and flattening same. Cutting theflattened tube 150 perpendicular to the side gussets 38 to a firstpredetermined length 154, thereby forming a bag blank 158. The bag blank158 has front 14 and rear 18 walls, front and rear top edges 30, frontand rear bottom edges 34, first 22 and second 26 side edges. Forming acrease line 166 in the bag blank 158. The crease line 166 is parallel tothe bottom edges 34 and spaced upwardly from the bottom edges 34 byapproximately one half of a width 170 of one of the side gussets 38.Slitting the bag blank 158 from the bottom edges 34 of the walls 14, 18to the crease line 166 at each intersection of the front 14 and rear 18walls and the side gussets 38. Folding lower corners 54 of the each sidegusset 38 outwardly to the crease line 166 and together to form downwardpointing triangular panels 58. Folding the triangular panels 58 inwardlyfrom the side gussets 38 at the crease line 166. Folding lower portions46 of the front 14 and rear 18 walls inwardly from the crease line 166.Sealing the front 14 and rear 18 walls together adjacent the front andrear bottom edges 34 to form a bag bottom 42. Sealing the bag bottom 42to the side gussets 38 adjacent the crease line 166 and upper edges 62of the triangular panels 58. Sealing the triangular panels 58 to anupper surface 66 of the bag bottom 42.

(15) Still another variant of the method, as illustrated in FIG. 5,includes the additional step of folding the bag blank 158 inwardly atthe side gussets 38 and upwardly from either of the front wall 14 andthe rear wall 18 at the crease line 166, to form a flattened bag 10.

(16) Yet another variant of the method, as illustrated in FIG. 6,includes the step of cutting at least one handle opening 74 in the bag10, the handle opening 74 extending through the front 14 and rear 18walls in an upper portion 78 of the bag 10.

(17) A further variant of the method includes the step of forming thebag 10 of a porous material 82.

(18) Yet a further variant of the method includes the step of formingmicroperforations 84 penetrating at least a portion of any of the bagwalls 14, 18 and side gussets 38.

(19) Still a further variant of the method, as illustrated in FIG. 7,includes the step of forming a plurality of ventilating openings 86penetrating at least a portion of any of the bag walls 14, 18 and sidegussets 38.

(20) Another variant of the method, as illustrated in FIG. 17, includesthe steps of: Joining the front wall 14 to the rear wall 18 at the topedges 30 of the bag walls 14, 18 and joining top edges 94 of the sidegussets 38, thereby forming an upper seal 90. Forming a U-shaped cutout98, the cutout 98 commencing at a first point 102 on the upper seal 90spaced from the first side edge 22 and extending downwardly toward thebottom edges 34, across an upper portion 78 of the bag walls 14, 18 andupwardly to a second point 106 on the upper seal 90 spaced from thesecond side edge 26, thereby forming an open bag mouth 110 and a pair ofbag handles 114 terminating at the upper seal 90.

(21) Still another variant of the method includes the step of cutting apair of apertures 118. Each of the apertures 118 penetrates the baghandles 114 at a point 122 spaced downwardly from the upper seal 90. Theapertures 118 permit the bag 10 to be suspended from a dispensing rack.

(22) Yet another variant of the method includes the step of forming acentral tab 130. The central tab 130 extends upwardly from at least oneof the front wall 14 and the rear wall 18 at the open mouth 110. Thecentral tab 130 has an opening 134 through it for suspending the bag 10.

(23) A further variant of the method includes the step of forming aweakened area 138. The weakened area 138 attaches the central tab 130 toat least one of the front wall 14 and the rear wall 18 at the open mouth110. The weakened 138 area permits the central tab 130 to be torn fromthe open mouth 110 of the bag 10 as the bag 10 is removed from adispensing rack.

(24) In a final variant of the method, As illustrated in FIG. 11,includes the step of forming the central tab 130 with a weakened area142. The weakened area 142 extends from the opening 134 to an edge 146of the central tab 130. The weakened area 142 parting under pressure asthe bag 10 is removed from a dispensing rack 126.

1. A square bottomed plastic bag, comprising: front and rearpolyethylene film walls, each of said front and rear walls having firstand second side edges, a top edge and a bottom edge; each of said bagshaving a pair of longitudinally oriented side gussets attached to saidfirst and second side edges; each of said bags having a flat,rectangular bottom formed of lower portions of said front and rear wallsand lower portions of said side gussets; lower corners of said each sidegusset being folded outwardly and together to form downward pointingtriangular panels; said triangular panels being folded inwardly fromsaid side gussets; lower portions of said front and rear walls beingfolded inwardly and sealed together to form the bag bottom; said bagbottom being sealed to said side gussets adjacent upper edges of saidtriangular panels; said triangular panels being sealed to an uppersurface of said bag bottom; and whereby, when said bag is opened, itwill stand erect upon said flat bottom.
 2. The square bottomed plasticbag as described in claim 1, wherein said bag is folded inwardly at saidside gussets and upwardly from either of said front wall and said rearwall at a point spaced upwardly from said bottom edge, to form aflattened bag.
 3. The square bottomed plastic bag as described in claim1, further comprising at least one handle opening, said handle openingextending through said front and rear walls in an upper portion of eachof said bags.
 4. The square bottomed plastic bag as described in claim1, wherein said bags are formed of a porous material.
 5. The squarebottomed plastic bag as described in claim 1, wherein said bags areformed of material having microperforations penetrating at least aportion of any of said bag walls and side gussets.
 6. The squarebottomed plastic bag as described in claim 1, wherein said bags have aplurality of ventilating openings penetrating at least a portion of anyof said bag walls and side gussets.
 7. The square bottomed plastic bagas described in claim 1, wherein said bag further comprises: an upperseal, said upper seal joining said front wall to said rear wall at saidtop edges of said bag walls and joining top edges of said side gussets;and a U-shaped cutout, said cutout commencing at a first point on saidupper seal spaced from said first side edge and extending downwardlytoward said bottom edges, across an upper portion of said bag walls andupwardly to a second point on said upper seal spaced from said secondside edge, thereby forming an open bag mouth and a pair of bag handlesterminating at said upper seal.
 8. The square bottomed plastic bag asdescribed in claim 7, wherein said bag further comprise a pair ofapertures, each of said apertures penetrating said bag handles at apoint spaced downwardly from said upper seal, said apertures permittingsaid bag to be suspended from a dispensing rack.
 9. The square bottomedplastic bag as described in claim 7, further comprising: a central tab,said central tab extending upwardly from at least one of said front walland said rear wall at said open mouth; and said central tab having anopening therethrough for suspending said bag from a dispensing rack. 10.The square bottomed plastic bag stack as described in claim 7, whereinsaid central tab is attached to at least one of said front wall and saidrear wall at said open mouth at a weakened area, said weakened areapermitting said central tab to be torn from said open mouth of said bagas said bag is removed from a dispensing rack.
 11. The square bottomedplastic bag stack as described in claim 10, wherein said central tabincludes a weakened area, said weakened area extending from said openingto an edge of said central tab, said weakened area parting underpressure as said bag is removed from a dispensing rack.
 12. A method ofmaking a square bottomed plastic bag, comprising the steps of: extrudinga tube of thermoplastic material; forming side gussets in said tube andflattening same; cutting said flattened tube perpendicular to said sidegussets to a first predetermined length, thereby forming a bag blank,said bag blank having front and rear walls, front and rear top edges,front and rear bottom edges, first and second side edges; slitting saidbag blank at intersections of said side gussets and said front and rearwalls from said front and rear bottom edges upwardly for a firstpredetermined distance; folding lower corners of said each side gussetoutwardly and together to form downward pointing triangular panels;folding said triangular panels inwardly from said side gussets; foldinglower portions of said front and rear walls inwardly; sealing said frontand rear wall together adjacent said front and rear bottom edges to forma bag bottom; sealing said bag bottom to said side gussets adjacentupper edges of said triangular panels; and sealing said triangularpanels to an upper surface of said bag bottom.
 13. The method of makinga square bottomed plastic bag, as described in claim 12, comprising theadditional step of folding said bag inwardly at said side gussets andupwardly from either of said front wall and said rear wall at a pointspaced upwardly from said bottom edge, to form a flattened bag.
 14. Amethod of making a square bottomed plastic bag, comprising the steps of:extruding a tube of thermoplastic material; forming side gussets in saidtube and flattening same; cutting said flattened tube perpendicular tosaid side gussets to a first predetermined length, thereby forming a bagblank, said bag blank having front and rear walls, front and rear topedges, front and rear bottom edges, first and second side edges; forminga crease line in said bag blank, said crease line being parallel to saidbottom edges and spaced upwardly from said bottom edges by approximatelyone half of a width of one of said side gussets; slitting said bag blankfrom said bottom edges of said walls to said crease line at eachintersection of said front and rear walls and said side gussets; foldinglower corners of said each side gusset outwardly to said crease line andtogether to form downward pointing triangular panels; folding saidtriangular panels inwardly from said side gussets at said crease line;folding lower portions of said front and rear walls inwardly from saidcrease line; sealing said front and rear wall together adjacent saidfront and rear bottom edges to form a bag bottom; sealing said bagbottom to said side gussets adjacent said crease line and upper edges ofsaid triangular panels; and sealing said triangular panels to an uppersurface of said bag bottom.
 15. The method of making a square bottomedplastic bag, as described in claim 14, comprising the additional step offolding said bag blank inwardly at said side gussets and upwardly fromeither of said front wall and said rear wall at said crease line, toform a flattened bag.
 16. The method of making a square bottomed plasticbag, as described in claim 12, further comprising the step of cutting atleast one handle opening in said bag, said handle opening extendingthrough said front and rear walls in an upper portion of said bag. 17.The method of making a square bottomed plastic bag, as described inclaim 12, further comprising the step of forming said bag of a porousmaterial.
 18. The method of making a square bottomed plastic bag, asdescribed in claim 12, further comprising the step of formingmicroperforations penetrating at least a portion of any of said bagwalls and side gussets.
 19. The method of making a square bottomedplastic bag, as described in claim 12, further comprising the step offorming a plurality of ventilating openings penetrating at least aportion of any of said bag walls and side gussets.
 20. The method ofmaking a square bottomed plastic bag, as described in claim 12, furthercomprising the steps of: joining said front wall to said rear wall atsaid top edges of said bag walls and joining top edges of said sidegussets, thereby forming an upper seal; and forming a U-shaped cutout,said cutout commencing at a first point on said upper seal spaced fromsaid first side edge and extending downwardly toward said bottom edges,across an upper portion of said bag walls and upwardly to a second pointon said upper seal spaced from said second side edge, thereby forming anopen bag mouth and a pair of bag handles terminating at said upper seal.21. The method of making a square bottomed plastic bag, as described inclaim 20, further comprising the step of cutting a pair of apertures,each of said apertures penetrating said bag handles at a point spaceddownwardly from said upper seal, said apertures permitting said bag tobe suspended from a dispensing rack.
 22. The method of making a squarebottomed plastic bag stack, as described in claim 20, further comprisingthe step of forming a central tab, said central tab extending upwardlyfrom at least one of said front wall and said rear wall at said openmouth, said central tab having an opening therethrough for suspendingsaid bag.
 23. The method of making a square bottomed plastic bag, asdescribed in claim 22, further comprising the step of forming a weakenedarea, said weakened area attaching said central tab to at least one ofsaid front wall and said rear wall at said open mouth, said weakenedarea permitting said central tab to be torn from said open mouth of saidbag as said bag is removed from a dispensing rack.
 24. The method ofmaking a square bottomed plastic bag, as described in claim 22, furthercomprising the step of forming said central tab with a weakened area,said weakened area extending from said opening to an edge of saidcentral tab, said weakened area parting under pressure as said bag isremoved from a dispensing rack.